FUKAO, A., HISAMICHI, S., KOMATSU, S., SHIMIZU, H., SATOH, H., NAKATSUKA, H., WATANABE, T., FUJISAKU, S., ICHINOWATARI, Y., KURODA, S., IDA, Y., SUDA, S., KATO, K. and IKEDA, M. Comparison of Characteristics between Frequent Participantsand Non-Participants in Screening Program for Stomach Cancer. Tohoku J. Exp. Med., 1992, 166 (4), 459-469-To clarify the differences in characteristics between participants and non-participants in the screening program for stomach cancer, life-style and medical histories were compared among 20, 169 subjects who lived in an urban area (Sendai) and a rural area (Wakuya and Tajiri) in Miyagi Prefecture, Japan. All subjects were classified into three groups according to the frequency of participation in the screening program during the last 5 years; i.e., frequent participating group (FPG) for 4 or 5 times, reference group (RG) for 1-3 times and non-participating group (NPG) for 0 times. Subjects in the FPG consumed more milk and green-yellow vegetable whereas those in the NPG consumed less these foods. The age-adjusted proportions of present smokers were higher in the NPG but lower in the FPG significantly. The proportions of subjects who had parental histories of all cancers and stomach cancer and past history of gastro-duodenal ulcer were higher in the FPG and lower in the NPG. To control influences among the variables a stepwise multiple regression analysis was done, and it revealed that smoking and parental history of cancers were strong predictors to explain the frequency of participation.